More documentation for #70

Adds CLOB & BLOB SQL Types to Tips & Tricks section with example of 
`ReadableColumn` extension and reference to helper/column reader in 
`next.jdbc.result-set`.

CHANGELOG.md

@@ -6,7 +6,8 @@ Only accretive/fixative changes will be made from now on.
 
 The following changes have been committed to the **master** branch since the 1.0.9 release:
 
-* Address #70 by adding `next.jdbc.result-set/clob-column-reader` and `next.jdbc.result-set/clob->string` helper to make it easier to deal with `CLOB` column data.
+* Fix link to **All The Options** in **Migration from `clojure.java.jdbc`**. PR #71 (@laurio).
+* Address #70 by adding **CLOB & BLOB SQL Types** to the **Tips & Tricks** section of **Friendly SQL Functions** and by adding `next.jdbc.result-set/clob-column-reader` and `next.jdbc.result-set/clob->string` helper to make it easier to deal with `CLOB` column data.
 * Update `org.clojure/java.data` to `"0.1.4"` (0.1.2 fixes a number of reflection warnings).
 
 ## Stable Builds

doc/friendly-sql-functions.md

@@ -229,7 +229,41 @@ By default, for compatibility with their default adapter (`clojure.java.jdbc`),
 
 ## Tips & Tricks
 
-This section will accrue various tips and tricks that make it easier to use `next.jdbc` with a variety of databases. It will be organized by database.
+This section will accrue various tips and tricks that make it easier to use `next.jdbc` with a variety of databases. It will be mostly organized by database, but there are a few that are cross-database and those are listed first.
+
+### CLOB & BLOB SQL Types
+
+Columns declared with the `CLOB` or `BLOB` SQL types are typically rendered into Clojure result sets as database-specific custom types but they will implement `java.sql.Clob` or `java.sql.Blob` (as appropriate). In general, you can only read the data out of those Java objects during the current transaction, which effectively means that you need to do it either inside the reduction (for `plan`) or inside the result set builder (for `execute!` or `execute-one!`). If you always treat these types the same way for all columns across the whole of your application, you could simply extend `next.jdbc.result-set/ReadableColumn` to `java.sql.Clob` (and/or `java.sql.Blob`). Here's an example for reading `CLOB` into a `String`:
+
+```clojure
+(extend-protocol rs/ReadableColumn
+  java.sql.Clob
+  (read-column-by-label ^String [^java.sql.Clob v _]
+    (with-open [rdr (.getCharacterStream v)] (slurp rdr)))
+  (read-column-by-index ^String [^java.sql.Clob v _2 _3]
+    (with-open [rdr (.getCharacterStream v)] (slurp rdr))))
+```
+
+There is a helper in `next.jdbc.result-set` to make this easier -- `clob->string`:
+
+```clojure
+(extend-protocol rs/ReadableColumn
+  java.sql.Clob
+  (read-column-by-label ^String [^java.sql.Clob v _]
+    (clob->string v))
+  (read-column-by-index ^String [^java.sql.Clob v _2 _3]
+    (clob->string v)))
+```
+
+As noted in [Result Set Builders](/doc/result-set-builders.md), there is also `clob-column-reader` that can be used with the `as-*-adapter` result set builder functions.
+
+No helper or column reader is provided for `BLOB` data since it is expected that the semantics of any given binary data will be application specific. For a raw `byte[]` you could probably use:
+
+```clojure
+    (.getBytes v 1 (.length v)) ; BLOB has 1-based byte index!
+```
+
+Consult the [java.sql.Blob documentation](https://docs.oracle.com/javase/8/docs/api/java/sql/Blob.html) for more ways to process it.
 
 ### MySQL
 

src/next/jdbc/result_set.clj

@@ -14,7 +14,6 @@
   Also provides the default implemenations for `Executable` and
   the default `datafy`/`nav` behavior for rows from a result set."
   (:require [clojure.core.protocols :as core-p]
-            [clojure.java.io :as io]
             [next.jdbc.prepare :as prepare]
             [next.jdbc.protocols :as p])
   (:import (java.sql Clob
@@ -241,7 +240,7 @@
 (defn clob->string
   "Given a CLOB column value, read it as a string."
   [^Clob clob]
-  (with-open [rdr (io/reader (.getCharacterStream clob))]
+  (with-open [rdr (.getCharacterStream clob)]
     (slurp rdr)))
 
 (defn clob-column-reader